The gunman was dead. Beside him, two semiautomatic pistols, extra magazines and a backpack.
Mainak Sarkar, a former doctoral student, had killed himself after storming through a UCLA building and fatally shooting a highly regarded professor inside a small fourth-floor office.
But the note Sarkar left behind kept authorities on edge. It listed a home address in St. Paul, Minn., nearly 2,000 miles away. There was also a request. Could someone check on his cat?
That led authorities to search the 38-year-old’s home, where they discovered a “kill list” with three names: William Klug, the professor fatally shot Wednesday; another UCLA professor, who is...